Wall-mounted air conditioner indoor unit

A wall-mounted air conditioner indoor unit, comprising a front housing and a rear housing forming a housing of the indoor unit, the housing being provided with main air intake portions, and heat exchangers being disposed inside the housing, wherein a mixed air outlet is formed in a lower portion of the front housing, a non-hot exchange air inlet is formed on the rear housing at a position corresponding to the mixed air outlet, an air delivery apparatus is disposed inside the housing, the air delivery apparatus comprises at least two air-duct bodies each having front and rear openings, the air-duct bodies are sequentially arranged next to one another to form a throughway air passage therebetween, the throughway air passage connects the mixed air outlet and the non-hot exchange air inlet, a hot exchange air passage is formed between two adjacent air-duct bodies of the air-duct bodies, a size of an upper portion of the hot exchange air passage is greater than that of a lower portion of the hot exchange air passage, thereby forming a passage structure that is wide at the upper portion and narrow at the lower portion, a volute and a centrifugal fan located inside the volute are disposed inside the housing and above the air delivery apparatus, an air output portion of the volute faces the hot exchange air passage, the air output portion of the volute includes a surrounding portion that extends to the air delivery apparatus and surrounds the hot exchange air passage, and air mixed cavities are formed between the surrounding portion and the hot exchange air passage.